I mean: Domino's also has a limited staff.
And most of the process is very similar between Domino's and Kroger.
Just pick out a selection of stuff on a website, and order it. They both provide timely status updates of that order. They both have varying staff levels and workloads. They both certainly have days when they're running very far behind, and days when they feel like they don't have much to keep busy with.
They both have pickup and delivery options; sometimes, with different per-item prices, deals, or fees for each option.
But that's where the similarities end.
If a person orders a pizza at 6:05 and it happens to be ready by 6:30, Domino's doesn't make that person wait until 8:00 to pick it up. They want it gone; the sooner, the better. A person can pick it up (in the store, or they'll bring it out to the car) as soon as it is ready. Domino's does not want any queues at all; neither inbound, nor outbound. And this makes sense: They're in the business of selling pizzas, not storing pizzas.
Kroger isn't like that. If a person orders groceries at 6:05 and the order is ready by 6:30, then: They hold the groceries hostage until 8:00. It's as if an otherwise-complete order just isn't ripe to be picked up by a customer until it has had time to purge itself in a waiting area -- regardless of workload. The queue is mandatory, and is governed not by the physical readiness of the order but instead by the clock on the wall.
This is inconceivably stupid and unnecessary. It serves no benefit to me, nor to the corporation, nor to the employees that work for that corporation. One might think that they'd be aware that they're in the business of selling groceries, but this mandatory purgatory shows otherwise.
(I'll betcha McMaster-Carr doesn't sit on stuff while a clock runs. That's a Kroger specialization. :) )